1. Field of the Invention
The present invention relates to a throttle valve control device which detects an abnormality of a double-system sensor including a main sensor and a sub-sensor having characteristics with the opposite polarities.
2. Description of the Related Art
Japanese Laid-Open Publication No. 4-214949 discloses using two potentiometers which have characteristics with the opposite polarities as an opening angle sensor. The Publication discloses a device which can detect a disconnection or a short circuit occurring in each of the two potentiometers as an abnormality of the opening angle sensor.
However, the Publication has not considered the case of a short circuit occurring between output terminals of the two potentiometers.
A short circuit between output terminals of a double-system sensor may occur on a route between wire harnesses or inside a component. When such a short circuit occurs, the output voltage of the double-system sensor abruptly changes in a large amount. This large abrupt change may greatly affect the throttle valve control.
In view of the foregoing, the objective of the present invention is to provide a throttle valve control device which can properly detect a short circuit between output terminals of a double-system sensor.